乱码问题总结

来源：互联网发布：最红网络歌曲 2017 编辑：程序博客网时间：2024/06/10 06:42

>>1.直接访问jsp页面乱码

这是因为jsp文件的头部：

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

默认pageEncoding="ISO8859-1",把它改成UTF-8就可以正常显示中文了。

>>2.客户端向服务器传输的数据乱码

在Servlet中直接执行下面代码为出现乱码问题：

Sring username = request.getParameter("username");

要在这条语句之前设置一下request的编码方式：

request.setCharacterEncoding("UTF-8");String username = request.getParameter("username");

>>3.服务器返回给浏览器的数据显示乱码，这时候在执行返回操作之前设置一下response的编码：

response.setContentType("text/html;charset=UTF-8");

PrintWriter out = response.getWriter();out.println("原有的中文<br>");out.println("从客户端获得的用户名：" + username);out.flush();out.close();

>>4.要解决乱码问题，要进行上述的一系列设置，很麻烦，可以用过滤器解决乱码问题：

过滤器类代码：

package com.autonavi.filter;import java.io.IOException;import javax.servlet.Filter;import javax.servlet.FilterChain;import javax.servlet.FilterConfig;import javax.servlet.ServletException;import javax.servlet.ServletRequest;import javax.servlet.ServletResponse;public class CharacterEncodingFilter implements Filter {private FilterConfig config ;private String encoding = "ISO-8859-1";public void destroy() {encoding = null;}public void doFilter(ServletRequest request, ServletResponse response,FilterChain chain) throws IOException, ServletException {request.setCharacterEncoding(encoding);response.setContentType("text/html;charset=" + encoding);chain.doFilter(request, response);}public void init(FilterConfig config) throws ServletException {this.config = config;String s = config.getInitParameter("encoding");if(s != null){encoding = s;}}}

用于测试的一个Servlet代码:

package com.autonavi.servlet;import java.io.IOException;import java.io.PrintWriter;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class TestServlet extends HttpServlet {public void destroy() {super.destroy(); // Just puts "destroy" string in log}public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {doPost(request, response);}public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {//request.setCharacterEncoding("UTF-8");//response.setContentType("text/html;charset=UTF-8");String username = request.getParameter("username");PrintWriter out = response.getWriter();out.println("原有的中文<br>");out.println("从客户端获得的用户名：" + username);out.flush();out.close();}public void init() throws ServletException {}}

发送请求jsp代码：

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <head>    <base href="<%=basePath%>">        <title>My JSP 'index.jsp' starting page</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0">    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><!--<link rel="stylesheet" type="text/css" href="styles.css">-->  </head>    <body>    <form id="form" name="form" method="post" action="http://localhost:8081/filter/servlet/testServlet">    <table>    <input type="text" name="username" id="username"/>    <input type="submit" name="提交" value="提交" />    </table>    </form>  </body></html>

web.xml代码:

<?xml version="1.0" encoding="UTF-8"?><web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"><filter><filter-name>CharacterEncodingFilter</filter-name><filter-class>com.autonavi.filter.CharacterEncodingFilter</filter-class><init-param><param-name>encoding</param-name><param-value>UTF-8</param-value></init-param></filter><filter-mapping><filter-name>CharacterEncodingFilter</filter-name><url-pattern>/*</url-pattern></filter-mapping>  <servlet>    <servlet-name>TestServlet</servlet-name>    <servlet-class>com.autonavi.servlet.TestServlet</servlet-class>  </servlet>  <servlet-mapping>    <servlet-name>TestServlet</servlet-name>    <url-pattern>/servlet/testServlet</url-pattern>  </servlet-mapping>  <welcome-file-list>    <welcome-file>index.jsp</welcome-file>  </welcome-file-list></web-app>

这里要注意有几点需要注意：

1.刚开始执行总是显示乱码，后来查到原因是因为过滤器CharacterEncodingFilter中缺少这句代码：

response.setContentType("text/html;charset=" + encoding);

2.要以表单的形式发送请求,否则过滤器不起作用，若是以url的方式传递参数，则要在Tomcat相应位置加上：URIEncoding="UTF-8"

3.表单的请求方法method必须为post，不然过滤器也不会起作用